34704 datasheet(23/54 Pages) FREESCALE

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Analog Integrated Circuit Device Data

Freescale Semiconductor

34704

FUNCTIONAL DESCRIPTION

FUNCTIONAL INTERNAL BLOCK DESCRIPTION

See Power-Up Sequence on page 28 for more details on

when REG3 is powered up in the sequence.

The switcher will operate in DCM at very light loads to

allow pulse skipping.

VOUT3 will be discharged every time the regulator is

shutting down and it will be held low by the discharge FET as

long as possible.

Characteristics

• It powers up directly from the battery

• Operates at a switching frequency equals to FSW1

• Drives integrated low RDS(ON) N-channel power

MOSFETs (NHV_HC) as its output stage

• The output is ±4% accuracy

• Output voltage is adjustable by means of an external

resistor divider

• The output can be adjusted up or down at 2.5% steps to

achieve from +17.5% to -20.0% on each direction allowing

Dynamic Voltage Scaling using the I2C DVS register.

• An extra fine voltage scaling in 0.5% steps helps to adjust

down the output voltage as low as 40%.

• Uses a bootstrap network with an internal diode to power

its switch MOSFET

• All gate drive circuits are supplied from VG.

• Uses integrated compensation.

• The output is monitored for under-voltage and over-

voltage conditions

• The output is monitored for over-current and short-circuit

conditions

• The regulator is monitored for over-temperature conditions

Operation Modes

The switcher will be active when:

• VG is in regulation AND

• There is no GrpB shutdown command through the I2C

interface AND

• No faults exist that would cause GrpB to shut down

REG4

This is a 4-switch synchronous buck-boost PWM voltage-

mode control DC/DC regulator.

See Power-Up Sequence on page 28 for more details on

when REG4 is powered up in the sequence.

The switcher will operate in DCM at very light loads to

allow pulse skipping.

VOUT4 will be discharged every time the regulator is

shutting down and it will be held low by the discharge FET as

long as possible.

Characteristics

• It powers up directly from the battery

• Operates at a switching frequency equals to FSW1

• Drives integrated low RDS(ON) N-channel power

MOSFETs (NHV_HC) as its output stage

• The output is ±2% accuracy

• Output voltage is adjustable by means of an external

resistor divider

• The output can be adjusted up or down at 2.5% steps for

a total of +17.5% to -20.0% on each direction allowing

Dynamic Voltage Scaling.

• Uses bootstrap networks with an internal diode to power

its high side MOSFETs

• All gate drive circuits are supplied from VG.

• Uses external compensation

• The output is monitored for under-voltage and over-

voltage conditions

• The output is monitored for over-current and short-circuit

conditions

• The regulator is monitored for over-temperature conditions

Operation Modes

The switcher will be active when:

• VG is in regulation AND

• There is no GrpB shutdown command through the I2C

interface AND

• No faults exist that would cause GrpB to shut down

REG5

This is a 4-switch synchronous buck-boost PWM voltage-

mode control DC/DC regulator.

See Power-Up Sequence on page 28 on for more details

on when REG5 is powered up in the sequence.

The switcher will operate in DCM at very light loads to

allow pulse skipping.

VOUT5 will be discharged every time the regulator is

shutting down and it will be held low by the discharge FET as

long as possible.

Characteristics

• It powers up directly from the battery

• Operates at a switching frequency equals to FSW1

• Drives integrated low RDS(ON) N-channel power

MOSFETs (NHV_HC) as its output stage

• The output is ±2% accuracy

• Output voltage is adjustable by means of an external

resistor divider

• The output can be adjusted up or down at 2.5% steps for

a total of +17.5% to -20.0% on each direction allowing

Dynamic Voltage Scaling.

• Uses bootstrap networks with an internal diodes to power

its high side MOSFETs

• All gate drive circuits are supplied from VG.

• Uses external compensation

• The output is monitored for under-voltage and over-

voltage conditions

34704 Datasheet(PDF) 23 Page - Freescale Semiconductor, Inc

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